Multi-channel pintle valve

ABSTRACT

A multi-channel valve uses a single drive motor to translate a single actuator assembly coupling multiple pintle valves for metering the same amount of media through each channel. The actuator assembly includes a swivel base mounting two or more clevis and nut arrangements coupled to the pintles. The actuator assembly translates the pintles the same distance. The clevis and nut joints can pivot and slide with respect to the swivel base to provide four degrees of freedom between the pintles to significantly reduce binding or side loading on one or both pintles. A stop cushioning assembly is provided to prevent jamming at the interface of the actuator assembly and a motor driven drive assembly.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims benefit to U.S. provisional applicationSer. No. 60/357,152 filed Feb. 14, 2002.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] 1. Technical Field

[0004] The present invention relates to metering valves, and inparticular, to pintle valves, such as can be used to meter liquid orgaseous fuel in air and space vehicles.

[0005] 2. Description of the Related Art

[0006] Valves for metering fuel and other combustible media to enginesin aircraft and spacecraft are well known in the art, see eg., U.S. Pat.No. 6,250,602, assigned to the assignee of the present invention andhereby incorporated by reference as though fully set forth herein. Suchvalves are used to control the rate at which pressurized fuel, in aliquid or gaseous state, is supplied to inlet orifices in the enginecombustion chambers. The valves are relied upon to provide consistentand rapid control of flow rates of fuel at ignition and during sustainedoperation. Their operation is critical to proper performance of thevehicle. Poor valve operation can result in unstable engine performanceand possible failure.

[0007] These valves can have movable stem-like valve members, orpintles, aligned with the outlet port of the valve for controlling therate at which fuel flows to the engine. Pintle type valves are typicallyless affected by the temperatures and pressures of the fuel passingthrough the fuel chamber of the valve, due to their contoured head andaxial movement parallel to the media.

[0008] The pintles are moved between extended and retracted positions bya drive/actuator system, which can be can be a electric, mechanical,hydraulic, pneumatic or combinations thereof. Typical pintle meteringvalves, such as in the '602 patent, require a separate actuator systemfor each pintle valves. Thus, in applications requiring metering ofmultiple flow channels, separate actuators must be used. The numerousactuators add cost, size and weight to the metering system. In someapplications, such as air and space vehicles, for example vehicles withsupersonic combustion ramjet (“scramjet”) engines, space and weight mustbe minimized as much as possible, thus making conventional valvesundesirable.

[0009] Another problem with separate valves or valve channels is flowdivision deviation, which occurs when the flow through each valve in amulti-valve system is not identical. Slight deviations between the flowvolumes or rates of the valves can significantly adversely impactperformance in certain applications. For example, it is critical tominimize flow deviation between the valves metering fuel to the multiplezones of the combustion chamber in a scramjet engine.

SUMMARY OF THE INVENTION

[0010] The present invention provides an improved metering valveparticularly designed to consolidate actuation of multiple separate ormulti-channel valves.

[0011] Specifically, the invention provides a multi-channel meteringvalve having a housing defining two valve channels with correspondingoutlet ports. Two valve members are disposed in the two valve channelsand are movable along stroke axes to open and close off communication tothe respective the outlet ports. An actuator assembly has two movablejoints coupled to the valve members and is moved by a drive assembly totranslate the valve members along their associated second stroke axis.

[0012] In one preferred form, the valve members are pintles having acontoured head. The heads of the pintles are shaped and sized to seatagainst and close off a through of a venturi passageway upstream fromthe outlet ports. The venturi passageway provides sonic velocity flowthrough the throat to reduce noise without high pressure losses in thenozzle.

[0013] In another preferred form, each movable joint includes a clevisand nut arrangement that can pivot about and slide along a clevis axisessentially coplanar with and perpendicular to the stroke axes.Preferably, the actuator assembly includes a swivel base valve membersupporting structure to which the clevis and nut arrangements aremovable connected. A stem of each clevis fits into an associated openingin the swivel base along a peripheral edge defining at least twoopposite facing surfaces parallel to the stroke axes. An opposite forkedend of the clevis mounts the nuts at tapered ears, which allow the nutto pivot and translate slightly with respect to the clevis. Preferably,this arrangement provides four degrees of freedom between each valve andthe drive assembly, namely translation and rotation of each clevis withrespect to the swivel base and translation and rotation (although to alesser degree) of each nut with respect to its associated clevis. Eachnut has a threaded bore for coupling to the valve member directly or toan intermediate drive rod.

[0014] The quantity of valve members and movable joints can be more thantwo depending on the number of channels in the valve. The principle ofoperation is the same regardless of the number of channels, albeit thevalve member supporting structure (swivel base) will likely vary in sizeand shape depending on the number of channels in the valve. For example,a two channel valve may have a straight bar swivel base, a four channelvalve may have a cross or square block shaped swivel base and a five ormore channel base may have a disc shaped swivel base.

[0015] In yet another preferred form, the valve includes an anti-rotatedshaft driven by the drive assembly to translate the actuator assemblyessentially parallel to the stroke axes. Preferably, the shaft extendsthrough a central opening in the swivel base to which it is fixedlysecured. The shaft preferably has a slot receiving an anti-rotation pin.A drive motor turns a drive nut engaging a threaded end of the shaft toimpart translation to the actuator assembly and the valve members.

[0016] In still another preferred form, the valve includes a stopcushioning assembly providing non-jamming stops that may otherwise occurin the event the motor overdrives the actuator assembly. The cushioningassembly preferably includes two cups each containing two preloadedsprings mounted about the shaft on each side of the anti-rotation pinallowing translation of the pin parallel to the stroke axes.

[0017] The present invention thus provides a highly accurate meteringvalve using a single motor and actuator to drive the valve memberscontrolling flow through the multiple channels of the valves. Theactuator assembly drives the valve members nearly identical distances tometer nearly identical volumes of media through all channels with littleor no play in the primary direction of translation (along the strokeaxes). Flow division deviation is further minimized by the movableclevis and nut joints for each valve member providing restrainedmovement to reduce or eliminate side-loading or binding on one valvemember due to loading on another valve members.

[0018] These and still other advantages of the invention will beapparent from the detailed description and drawings. What follows is apreferred embodiment of the present invention. To assess the full scopeof the invention the claims should be looked to as the preferredembodiment is not intended as the only embodiment within the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1. is a full cross-sectional view of the multi-channel valveaccording to the present invention shown in a fully closed position;

[0020]FIG. 2 is a enlarged partial cross-sectional view showing driveand stop cushioning assemblies of the valve;

[0021]FIG. 3A is an exploded assembly view of an actuator assembly ofthe valve;

[0022]FIG. 3B is an assembled view of the actuator assembly of FIG. 3A;

[0023]FIG. 4 is an enlarged partial cross-sectional view showing onevalve assembly in a fully opening position;

[0024]FIG. 5 is a partial cross-sectional view taken along line 5-5 ofFIG. 1;

[0025]FIG. 6 is a partial cross-sectional view taken along line 6-6 ofFIG. 1 with a valve housing end plate shown cut away; and

[0026]FIG. 7 is a partial cross-sectional view taken along line 7-7 ofFIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0027] Referring to FIG. 1, the present invention provides amulti-channel (shown with two channels 96) metering valve 10. Generally,the valve 10 includes a valve housing 12 having an open end 14 to whichis connected a motor mount 16. These components and all those describedherein are preferably constructed of materials having low weight buthigh resistance to contaminants as need to withstand the harshenvironments common to air and space applications. The housing 12 andmotor mount 16 mount or contain the motor 18 and the primary assembliesof the valve 10, including a drive assembly 20, an actuator assembly 22,multiple (in this case two) identical valve assemblies 24 and a stopcushioning assembly 26. FIG. 1 shows the valve assemblies 24 in thefully closed position.

[0028] The motor 18 driving the drive assembly 20 is preferably a DCelectric motor 22, but could be any other drive means, such as ahydraulic or pneumatic motor. Preferably, the motor 18 includes aposition transducer (not shown) providing a position feedback signal, asknown in the art, to the master computer/controller (not shown). Thefront face of the motor 18 is bolted to a first flanged end 28 of themotor mount 16, the second flanged end 30 of which is bolted to the openend 14 of the housing 12 and sealed by an o-ring 31. The motor 18 turnsa drive shaft 32, and thereby the rotatable components of the driveassembly 20, about a shaft axis 34.

[0029] Referring to FIGS. 1 and 2, in the preferred construction shownin the drawings, the drive shaft 32 mounts a shaft coupler 36 (securedby a set screw 37) which in turn mounts a guide pin 38 keyed to anannular drive nut 40 disposed in the center of the motor mount 16. Thedrive nut 40 is rotatably disposed inside of a spacer sleeve 42 and thecenter of a thrust block 44, both of which are held in place by a clampnut 46 threaded to the inside of the motor mount 16. Operating the motor18 turns the drive shaft 32, shaft coupler 36 and guide pin 38, eitherclockwise or counterclockwise, which in turn rotate the drive nut 40.The drive nut 40 has a central flange 48 on each side of which is anassembly of two thrust bearings 50 sandwiched between two thrust washers52. The outer races of the thrust bearings 50 are fixed by interferenceto the spacer sleeve 42, and thus to the motor mount 16, while the innerraces are free to rotate with the drive nut 40. The drive nut 40 (viaflange 48) and the thrust bearings 50 act to transfer (through theactuator assembly 22) to the motor mount 16 forces arising from pressureon the valve assemblies 24 that would otherwise be distributed to themotor 20. This redistribution of the pressure loads promotes accurateand responsive valve positioning and helps prolong the operational lifeof the motor 18. In addition, the components of the drive assembly 20(except for the motor 18) are enclosed in the motor mount 16 andisolated from the metered media and other contaminants to ensurelow-friction and militate against premature wear and operationalfailure.

[0030] The drive nut 40 has a threaded bore 54 concentric with the shaftaxis 34, which engages a threaded end 56 of a main shaft 58 coupling thedrive 20, actuator 22 and stop cushioning 26 assemblies. The actuatorassembly 22 is fixedly mounted to the main shaft 58 by at anintermediate location by a double “D” key 60 and slot 61 arrangement (asshown in FIGS. 3B and 5) as well as a nut 62 threaded to an intermediatethreaded section 63 of the main shaft 58. In particular, the slot 61 isformed in a downstream side of a swivel base 64 intersecting a centralopening 66 therethrough through which the main shaft 58 extends. Theswivel base 64 is thus disposed essentially perpendicular to the shaftaxis 34. In the two channel embodiment described herein, the swivel base64 is a straight bar, however, its configuration can be changed asneeded for valves with three or more channels. For example, the swivelbase 64 may be Y-shaped for a three channel valve, cross-shaped for afour channel valve and disc-shaped for a five or more channel valve. Inany case, the swivel base 64 will mount two or more (depending on thenumber of channels) identical movable joints 68 coupling the valveassemblies 24 to the swivel base 64. The movable joints 68 are designedto provide one or more degrees of freedom between the actuator 22 andvalve 24 assemblies (as will be described), while maintaining precisepositioning control with little play or slop in the direction that theentire actuator assembly 22 translates.

[0031] Referring to FIGS. 1 and 3A-3B, in one preferred form eachmovable joint 68 is made of a clevis member 70 and a slotted nut 72arrangement. Each clevis 70 has a cylindrical stem 74 at one end and anopposite forked end 76 to define a Y-shaped structure. The prongs of theforked end 76 have outwardly extending ears 78 that are tapered to amiddle peak to fit in line contact against the opposing walls of twoslots 80 in the nut 72 on opposite sides of a threaded bore 82 therein.The line contact engagement allows the nut 72 to pivot and translate (upand down in the drawings) slightly (until restrained by contact with theclevis 70) with respect to the clevis 70 about and along a nut axis 88.Each clevis 70 mounts to the swivel base 64 at a cylindrical opening 84extending through peripheral edge surfaces thereof. The clevis stems 74fit into these openings 84 to free pivot and slide therein. Thisarrangement thus provides for four degrees of freedom, namely pivotingand sliding of each clevis 70 about an axis 86 perpendicular to theshaft axis 32 as well as translating and pivoting of each nut 72 aboutaxes 88 perpendicular to both the shaft axis 32 and clevis axis 86. Themovable joints 68 reduce or eliminate cross-loading between the valveassemblies 24. For example, binding or side loading on one valveassembly from the pressurized media will be isolated from (nottransferred through the actuator assembly 22 to) the other valveassembly. While this arrangement provides some degree of flexibility toeliminate cross-loading, the range of movement of the movable joints 68is limited by interference of the mating clevis 70 and nut 72 componentsas well as by the connection of the nuts 72 to the valve assemblies 24.Accordingly, the construction of the actuator assembly 22 provides forprecise and responsive valve positioning by isolating the loading oneach valve assembly using joints with a restrained range of motion.

[0032] Referring to FIGS. 1 and 4, the actuator assembly 22 couples toeach of the (in this case two) valve assemblies 24, the components ofwhich are preferably made of stainless steel, by engagement of athreaded end 90 of a connecting rod 92 in the threaded bore 82 of theassociated nut 72. The connecting rods 92 extend through holes in an endplate 94 bolted to the open end 14 of the housing 12 into separate valvechannels 96. The end plate 94 encloses the valve housing 12 and securesseal blocks 98 in the channels 96. The seal blocks 98 have groovesholding two outer seals 100 (preferably o-rings) and two shaft seals 102(preferably Teflon® cap strip seals), which create a sliding seal withthe main shaft 58. The seals 100 and 102 isolate the gaseous or liquidmedia being metered from the components enclosed in the motor mount 16.The two sets of seals 100 and 102 are mounted on each side of apassageway 103 leading to an interstitial vent (or witness drain) forobservance of media leakage during maintenance checks.

[0033] The seal block 98 in turn secures a guide tube 104 in theassociated channel 96 which abuts an annular seal adapter 106 and anozzle module 108. The guide tube 104 defines a cylindrical innerpassageway 110 and has a transverse opening 112 allowing communicationbetween the inner passageway 110 and the supply inlet passageway 114(shown in phantom and including the enlarged passage area 115) receivingpressurized media from a supply tank (not shown). It should be notedthat the media can be any suitable liquid or gaseous media. When thevalve is to be used with scramjet engines, however, the media is agaseous hydrogen (with silane at ignition). JP-7, available fromrefining hydrocarbon based liquid, is an example of one common jet fuelformula naturally available as a liquid and can be transformed into agaseous state suitable for use with the present valve in a scramjetapplication. Note also that the valve 10 is useable in the harshoperating environment of scramjet engine application in which the mediacan reach 1000 psia and 1350° F.

[0034] The seal adapter 106 also defines an inner passageway 116 alignedwith that of the guide tube 104 and mounts an outer seal 118. The nozzlemodule 108 has two outer seals 120 and defines a venturi passageway 122having the characteristic narrowed throat 124 and tapered inlet andoutlet sections, the outlet defining an outlet port 126 that is isolatedfrom the that of the other channel(s), to which suitable fittings can bemounted to interface with transport lines (not shown). As is understoodin the art, the venturi passageway 122 enables the media to reach sonicvelocity at the throat 124, which prevents noise at the outlet port fromreaching the intake port with relatively small pressure loss between thesupply inlet 114 and the outlet port 126. The nozzle module 108 slidesinto the channel 96 and is threaded to the housing 12 from a back end128 with a spacer 129 therebetween.

[0035] The throat 124 of each venturi passageway 122 through the nozzlemodule 108 is closed by an elongated contoured head 130 of a pintle 132extending through inner passageway 110 of the guide tube 104 along astroke axis 134, essentially parallel to the shaft axis 34. A trailingend 136 of each pintle 132 threads into a threaded socket 136 in an end138 of the connecting rod 92. The connecting rod end 138 also defines acylindrical pocket 140 for a spacer sleeve 142 pressing a pintle seal144 (preferably a cap strip seal) against a flange 146. The pintle seal144 creates a sliding seal with the inner passageway 110 of the guidetube 104.

[0036] Referring now to FIGS. 1 and 2, the final assembly to bedescribed is the stop cushioning assembly 26 mounted in the housing 12around the main shaft 56. The stop cushioning assembly 26 includes anindex sleeve 148 disposed in a central cavity 150 of the housing 12concentric with the shaft axis 34. The index sleeve 148 has an edge slot152 at one end and a slots 154 at opposite intermediate wall locations.The index sleeve 148 is clocked to align the edge slot 152 with a radialrecess 155 on the open end 14 of the housing 12 extending radial outwardfrom the central cavity 150. An anti-rotation lug 156 is placed in theradial recess 155 and the edge slot 152 and is bolted to the housing 12to prevent rotation of the index sleeve 148 with respect to the housing12. The index sleeve 148 is pressed in abutment with the housing 12 bythe end plate 94 by pressing a spacer sleeve 156 against a flange of anannular end piece 158 abutting the index sleeve 148. The index sleeve148 holds two spring cups 160 opening in opposite directions and eachcontaining an inner 162 and an outer 164 coil spring. A second annularflanged end piece 166 and end piece 158 capture the springs 162 and 164in each cup and preloads them so that the cups abut opposite sides ofwalls defining the intermediate slots 154 between which is disposed anannular stop ring 168. The stop ring 168 has aligned openings in whichan anti-rotation pin 170 is disposed having an intermediate portiondisposed through a slot 172 in the main shaft 58 and ends extendingbeyond the stop ring 168 into the intermediate slots 154 in the indexsleeve 148. Note that the main shaft 58 extends beyond the stopcushioning assembly 26 in the central cavity 150, which can open throughto the back end 128 so that the main shaft 58 can drive a tandem valve.Otherwise, the central cavity 150 can be plugged (as shown) or formed tohave a closed end.

[0037] In operation, the motor 18 of the valve 10 is electricallycoupled to an electronic control unit (not shown). In the case of a jetor scramjet engine application, the control unit will be an integral ordiscrete part of a vehicle system computer, which provides input commandsignals to control the pintle positioning and thus flow of pressurizedfuel through the valve 10. According to the command input, the motor 18will turn the drive nut 40 which will engage the threaded end 56 of themain shaft 58. The anti-rotation pin 170 will prevent the main shaft 58from rotating by contact with the walls of the slot 172 and thus causethe main shaft 58 to translate. This in turn drives the actuatorassembly 22 to translate the moveable components of the valve assemblies24. In particular, it will move the pintles 132 between a fully openposition (as shown in FIG. 1) to a fully closed position (as shown inFIG. 4) in which the pintle head 130 fully seals off the throat 124 ofthe nozzle venturi. When the venturi passageway 122 is open, pressurizedmedia from a supply tank can enter the supply inlet passageways 114 ofthe valve 10, perhaps through lines connected to a manifold block (notshown) formed into or mounted to the housing 12, and pass into the valvechannels 96, around the pintles 132 (when open), through the venturipassageway 122 and out the outlet ports 126. Varying the location of thepintles 132 along the stroke axes 134 varies the volume of flow throughthe channels of the valve 10. While the inlet side can be separate or incommon, the outlet side of the valve 10 each valve channel 96 will beisolated from the others. The media can then be transported throughseparate lines or passageways to different zones or combustion chambersof the engine.

[0038] As discussed in detail above, the drive assembly 20 is designedto reduce thrust loads realized by the motor 18 and the actuatorassembly 22 is designed to eliminate cross-loading on the pintles 132.These features all work to provide nearly perfectly uniform pintleposition so that the media leaving each outlet port 126 is nearlyidentical in rate and volume, thus minimizing to a great extend flowdivision deviation. Pintle positioning (and thus metering accuracy) isfurther enhanced by the feedback signal (from the position transducer inthe motor 18) provided to the control unit. The control unit can thenexecute position correcting signals to the valve if the actual positionwas different than that of the command input.

[0039] The stop cushioning assembly 26 provides for non-jamming forwardand reverse stops in the event the input signal overdrives the motor 18in either direction, such as shown in FIG. 2. It does this by allowingthe anti-rotation pin 170 to translate in either direction slightlywithin the slots 154 of the index sleeve 148 so that main shaft 58 cantranslate slightly further in either direction rather than locking wheneither end of the slot 172 hits the pin 170. The springs 162 and 164absorb the energy from the main shaft 58 hitting the pin 170 and returnit to the default position after the main shaft 58 position iscorrected. Primarily, this prevents the mating threads of the drive nut40 and the main shaft 58 from locking together. It also reduces damageto or shearing of the anti-rotation pin 170 or main shaft 150 in theevent of an error condition.

[0040] The present invention thus provides a highly accurate meteringvalve using a single actuator to drive the valve members controllingflow through the multiple channels of the valves. The actuator assemblydrives the valve members uniformly to meter nearly identical volumes ofmedia through all channels. Flow division deviation is further minimizedby the movable clevis and nut joints for each valve member whichprovides a connection with nearly zero play in the direction oftranslation along shaft axis, while providing some degree of freedom toreduce or eliminate the side-loading or binding on one valve member dueto loading on another valve members.

[0041] It should be appreciated that merely a preferred embodiment ofthe invention has been described above. However, many modifications andvariations to this preferred embodiment will be apparent to thoseskilled in the art, which will be within the spirit and scope of theinvention. Moreover, the described scramjet engine application is onlyone of the many uses for the valve of the present invention; it is alsopossible for the valve construction described herein to be used to metergas or liquid media in other applications. Therefore, the inventionshould not be limited to the described embodiment. To ascertain the fullscope of the invention, the following claims should be referenced.

I claim:
 1. A multi-channel metering valve, comprising: a housingdefining a first valve channel having a first outlet port and a secondvalve channel having a second outlet port; first and second valvemembers in the respective first and second valve channels movable alongrespective first and second stroke axes to open and close offcommunication to the respective first and second outlet ports; anactuator assembly having a first movable joint coupled to the firstvalve member and a second movable joint coupled to the second valvemember; and a drive assembly moving the actuator assembly to translatethe first and second valve members along the respective first and secondstroke axes.
 2. The valve of claim 1, wherein the first and secondmovable joints each include a clevis member pivotal about a clevis axisessentially coplanar with and perpendicular to the first and secondstroke axes.
 3. The valve of claim 1, wherein the first and second valvemembers are pintles having a contoured head.
 4. The valve of claim 3,wherein the drive assembly provides a rotational input to the actuatorassembly to impart translation to the first and second pintles.
 5. Thevalve of claim 4, further including a main shaft connected to theactuator assembly, the main shaft being held against rotation and havinga threaded end and wherein the drive assembly includes a drive nutengaging the threaded end of the main shaft to translate the main shaftas the drive nut is rotated.
 6. The valve of claim 5, wherein the mainshaft has a slot through which extends an anti-rotation pin.
 7. Thevalve of claim 6, further including a stop cushioning assembly coupledto the main shaft allowing translation of the anti-rotation pin parallelto the first and second stroke axes.
 8. The valve of claim 6, furtherincluding a motor having a rotating shaft coupled to the drive assembly.9. The valve of claim 3, wherein the actuator assembly includes a swivelbase and wherein the first and second movable joints are pivotal withrespect to the swivel base.
 10. The valve of claim 9, wherein the firstand second movable joints are translatable with respect to the swivelbase.
 11. The valve of claim 9, wherein the swivel base extendsessentially perpendicular to the first and second stroke axes andwherein the first and second movable joints are translatable in adirection essentially perpendicular to the first and second stroke axes.12. The valve of claim 11, wherein first and second movable joints eachinclude a clevis having a stem at one end and an opposite forked end.13. The valve of claim 12, wherein the first and second movable jointseach further include a nut mounted to the forked end of the clevis andhaving a threaded bore for coupling to the respective first and secondpintles.
 14. The valve of claim 13, wherein each nut is mounted to betranslatable and pivotal with respect to its associated clevis.
 15. Thevalve of claim 14, wherein the swivel base has a peripheral edgedefining at least two opposite facing surfaces parallel to the first andsecond stroke axes through which extend first and second openings eachreceiving the clevis stem of the respective first and second movablejoints.
 16. The valve of claim 15, wherein each of the first and secondpintles includes a drive rod coupled to the threaded bore of theassociated nut.
 17. The valve of claim 16, wherein the swivel base is astraight bar.
 18. The valve of claim 1, further including ananti-rotated main shaft coupling the drive and actuator assemblies anddriven by the drive assembly to translate essentially parallel to thefirst and second stroke axes.
 19. The valve of claim 18, wherein theshaft has a slot receiving an anti-rotation pin.
 20. The valve of claim18, further including a stop cushioning assembly coupled to the mainshaft allowing translation of the anti-rotation pin parallel to thefirst and second stroke axes.
 21. The valve of claim 18, wherein theactuator assembly further includes a swivel base mounting the first andsecond movable joints and having a central opening extending parallel tothe first and second stroke axes to which the shaft is mounted.
 22. Thevalve of claim 3, wherein the first and second valve channels eachinclude a nozzle passageway defining a venturi opening having a narrowedthroat that can be sealed by the heads of the respective first andsecond pintles.
 23. The valve of claim 1, wherein the first outlet isisolated from the second outlet.
 24. The valve of claim 1, wherein eachof the first and second moveable joints provides at least one degree offreedom between the drive assembly and the respective first and secondvalve members.
 25. The valve of claim 24, wherein each of the first andsecond movable joints provides four degrees of freedom between the driveassembly and the respective first and second valve members, includingtranslation and rotation about each of two separate additional axes. 26.The valve of claim 25, wherein the two additional axes lie in a planeperpendicular to the a plane containing the first and second strokeaxes.
 27. A multi-channel metering valve, comprising: a valve housingdefining at least two valve channels each having a venture passagewayleading to an isolated outlet port; at least two pintles disposed in theat least two valve channels each extending along a stroke axis, thefirst and second pintles each having a contoured head sized to close offa throat of the venture passageway; a single actuator assembly having aswivel base to which are coupled at least two clevis members to beindependently movable with respect to the swivel base, each clevismember being coupled to one of the at least two pintles; and a driveassembly moving the actuator assembly to translate the at least twopintles essentially the same distance along its associated stroke axis.28. The valve of claim 27, wherein the swivel base extends essentiallyperpendicular to the stroke axes and is translatable in a directionessentially perpendicular to each stroke axis and wherein each clevis ispivotal with respect to the swivel base about a clevis axis essentiallycoplanar with and perpendicular to the stroke axes.
 29. The valve ofclaim 28, wherein each clevis can slide with respect to the swivel basealong the associated clevis axis.
 30. The valve of claim 29, whereineach clevis has a stem at one end disposed along the associated clevisaxis and an opposite forked end.
 31. The valve of claim 30, wherein theactuator assembly includes at least two nuts each mounted to the forkedend of one of the at least two clevis members and having a threaded borefor coupling to one of the at least two pintles.
 32. The valve of claim31, wherein each nut is mounted to be translatable and pivotal withrespect to its associated clevis.
 33. The valve of claim 32, wherein theswivel base has a peripheral edge defining at least two opposite facingsurfaces parallel to the stroke axes through each of which extend anopening receiving the stem of the associated clevis.
 34. The valve ofclaim 33, wherein the drive assembly includes a rotatable drive nut andfurther including a main shaft fixedly coupled to the swivel base andhaving an end engaged by the drive nut.
 35. The valve of claim 34,wherein the shaft is anti-rotated by a pin and slot connection.
 36. Thevalve of claim 35, further including a stop cushioning assembly mountedto the valve housing permitting restrained translation of ananti-rotation pin of the pin and slot connection in a direction parallelto the stroke axes.
 37. The valve of claim 27, further including anelectric motor.